脑源性神经营养因子基因沉默对HeLa细胞增殖和凋亡的影响

目的 以高表达脑源性神经营养因子(BDNF)的官颈癌细胞系HeLa细胞为模型,筛选针对BDNF基因的有效干扰RNA序列,并观察BDNF基因沉默对HeLa细胞增殖和凋亡的影响.方法 设计和构建两个针对人BDNF基因的siRNA真核表达载体,经酶切鉴定和DNA序列分析鉴定后用脂质体Lipofectamine 2000介导转染,将空载体质粒pGenesil-1和两个重组质粒pGenesil-shRNA-BDNF1、pGenesil-shRNA-BDNF2分别转染人人HeLa细胞(依次命名为P_0、P_1和P_2组);采用RT-PCR和Western blot法分别从mRNA水平和蛋白水平检测BDNF表达的变化;四甲基偶氮唑盐(MTT)法检测细胞的增殖水平;流式细胞仪和Hoechest 33258染色检测细胞凋亡.结果 成功构建了针对BDNF的siRNA真核表达载体.P_1组与未转染、P_0、P_2组相比,BDNF mRNA表达水平(F=48.19,P<0.01)和BDNF蛋白表达水平(F=13.74,P<0.01)均明显降低,P_2组则未达实验预期的干扰目的 (P>0.05).通过MTT实验,发现P_1组细胞生长速度明显减慢,增殖高峰后移;流式细胞术检测证实早期凋亡率P_1组(53.4±4.2)%]明显高于未转染组(0.8±0.4)%]、P_0组(5.1±1.8)%]和P_2组(7.9±2.4)%;F=269.77,P<0.01].结论 BDNF基因高表达于官颈痛细胞系HeLa细胞,BDNF基因沉默能明显增加HeLa细胞的凋亡并抑制其增殖,提示BDNF基因可能成为恶性肿瘤治疗的新靶点.

Effect of RNA interference targeting brain-derived neurotrophic factor gene on HeLa cell proliferation and apoptosis

Objective To screen effective sequences of short hairpin RNA on brain-derived neurotrophic factor (BDNF) gene and the effect of RNA interference on the proliferation and apoptosis of HeLa cells, a cervix carcinoma cell line with high expression of BDNF. Methods Two recombinant eukaryotic human-BDNF siRNA expression vectors were designed and constructed. Sequences were confirmed by restrictive endonuclease digestion and DNA sequencing. The empty vector pGenesil-1 and two recombinant plasmids, pGenesil-shRNA-BDNF1 and pGenesil-shRNA-BDNF2, were transfected into HeLa cells using Lipefectamine 2000 (groups:P_0, P_1 and P_2, respectively). The mRNA and protein levels of BDNF in HeLa cells were detected by RT-PCR and Western blot, respectively. The cellular proliferation rates were determined by MTT assay and the apoptotic rates were measured by flow cytometry and Hoechest 33258. Results The recombinant eukaryotic BDNF siRNA expression vectors were successfully constructed. The expression of mRNA and protein of BDNF in P_1 group were significantly decreased, comparing with non-transfected group, P_0 and P_2 groups ( F = 48. 19, P < 0. 01 ). P_2 group failed to meet the expected results(P >0. 05). In addition, the proliferation activity was reduced in P_1 group and the peak point of proliferation curve was prolonged. Moreover, the early cell apoptotic rates were statistically increased in P_1(53.4±4.2)%] VS. non-transfected (0.8±0.4)%], P_0(5.1±1.8)%] and P_2(7.9± 2.4)%] groups(F=269.77, P<0.01). Conclusion HeLa cells express a high level of BDNF. BDNF gene silencing by RNA interference increases the apeptosis of HeLa cells and inhibits cell proliferation, offering a possible target for efficient tumor therapy.